Emergency signaling device



Feb. 17, 1959 .J. VARLEY EMERGENCY SIGNALING DEVICE Filed May 21 1956 4NTENN/l 1 INVENTOR ,fo/m Var/6y ATTORNEYS 1 2,874,292 EMERGENCY SIGNALINGDEVICE John Varley, Huntington, N. Y., assignor to Skyline Products,Inc., Deer Park, N. Y., a corporation of New York Application May 21,1956, Serial No. 586,159 1 Claim. (Cl. 250-36) This invention relatesgenerally to a method and apparatus for emergency signaling and moreparticularly relates to a method and apparatus for transmitting anemergency signal which can indicate the geographic position of theperson signaling.

Present day highways often stretch across lonely areas where there issparse population resulting in little or no contact between theoccupants of an automobile on the highway and other human beings forlong periods. Often a motorist on one of these lonely highways willencounter mechanical difficulty with his vehicle, or. an accident willoccur requiring that immediate help be given the injured person.Immediate contact must be made with authorities who can furnish aid, butoften facilities for communication are not available. I

Police in the United States have attempted to cope with this problem invarious ways. Some highways have located thereon telephones whichdistressed motorists may use in order to call for help. This isunsatisfactory, however, since remote areas of highway do not alwayshave power lines available. Although these roads are well patrolled bypolice, the immediate requirement for aid cannot be met unless theperson or persons requiring aid can immediately signal to the policetheir geographic position so that aid can be rushed-to their preciselocation.

The invention herein disclosed has as its principal object the provisionof a method whereby one of a series of geographic locations along ahighway can be determined at a receiving station.

Another object of the present invention is to provide a method wherebysignals can be transmitted to a receiving station without the use ofinterconnecting wires.

A further object of this invention is the provision of a method ofcrystal controlled frequency modulation signaling which is completelyself-powered and easily integrated with any existing emergency signalingsystem.

Another object of this invention is the provision of a signaling devicewhich is self-contained and which does not require an experiencedoperator.

Still another object of the present invention is to provide a signalingdevice which requires no external supply of power or internal battery.

A further object of this invention is the provision of a signalingdevice which is compact and easily transportable .so that it may bequickly prepared for use in any desired location.

Another object of the present invention is to provide a signaling devicewhich is sturdy and rugged so that exposure to the elements will notadversely affect the device or alter a signal transmitted therefrom.

Still another object of the present invention is to provide a signalingdevice which is so designed that neither usage nor non-usage will altera signal transmitted therefrom.

The emergency signaling device and method of using the same is describedherein with reference to the drawings in which:

Fig. 1 is a perspective view of the emergency signaling device;

Fig. 2 is a functional block diagram of the emergency signaling device;

Fig. 3 is a circuit diagram of the oscillator section of the emergencysignaling device;

United States Patent 8O 2,874,292 Patented Feb. 17, 1959 Fig. 4 is aportion of the circuitry shown in Fig. 3; and

Fig. 5 is a detailed view of the power generator and coder portion ofthe emergency signaling device.

As shown in the figures and especially Fig. 1, the emergency signalingdevice consists of a box-like structure designated as 10 having a cover11 hingedly connected thereto. Situated within box 10 are all of thecomponents of the signaling device. Thus, a compact unit is achieved.

Antenna 12 extends from the top of box 10 and handle 13 extends from aside of the box. Antenna 12 is the output portion of the signalingdevice. From this antenna signals are transmitted to a central receivingstation, not shown in the drawings at which the coded signal is decodedso that the receiver can know the exact position of the person using theemergency signaling device.

Handle 13 is attached to shaft 14, which is connected through gearing 15to shaft 16 and power generator 17. Gearing 15 is so designed thatslight rotation of shaft 14 will effect many rotations of shaft 16 thusthere is a stepup ratio between shaft 14 and shaft 16. Power generator17 is any familiar D. C. generator known to the art of the type suchthat rotations of shaft 16 will develop a voltage potential betweenleads 18 and 19 which extend outwardly from generator 17.

Coder 20 is mechanically coupled to generator 17 by shaft 21 so thatrotation of shaft 16 will cause rotation of shaft 21. Coder 20 consistsof a rotary drum and brushes 22 and 23 which are electrically connectedto lines 19 and 26 respectively. Contactor 24 extends about theperiphery of coder drum 20 and during rotation of the drum iscontinually in contact with brush 22. Conducting portions such as 25 arealso peripherally positioned on drum 20 so that as drum 20 rotates theyintermittently contact brush 23. Conductor 24 and conductor portions 25are connected internally so that at each instance when brush 23 is incontact with a conducting portion 25 a connection between lines 19 and26 results and voltage which is across lines 18 and 19 is placed acrosslines 18 and 26. At any instance when brush 23 is not in contact with aconducting portion 25 the circuit is broken and no voltage appearsbetween leads 18 and 26 although potential is available between leads 18and 19.

The coding means shown is illustrative only and it should be understoodthat any coding means can be used to practice this invention. It isnecessary only that such coding means be capable of control of the poweroutput of generator 17 and be easily adaptable so that changes in thecoding can be made with a minimum of effort.

Each emergency signaling device is particularly coded so that uponreceipt of a signal therefrom, the receiver can know from whichsignaling device the signal came. The effect of this coding upon theoutput signal will be explained below.

A functional block diagram of the system is shown in Fig. 2. Powergenerator 17 transmits D. C. .power via coder 20 to audio frequencyoscillator 27 and radio frequency oscillator 28.

Audio frequency oscillator 27 can be any type of audio oscillator whichis designed so that oscillation will occur during the periods when poweris supplied to the system. By use of the coder 20 power from powergenerator 17 is intermittently applied and audio frequency oscillator 27only oscillates during the periods when such power is supplied.

Radio frequency oscillator 28 can be any radio frequency oscillatorwhich like audio frequency oscillator 27 will oscillate during periodswhen power is supplied thereto.

Thus oscillators 27 and 28 will only operate during the period whencoder 20 allows generated power from power generator .17 to be appliedthereto. Andie fre quency oscillator 27 and radio frequency oscillator28 are coupled together in such manner that oscillator 27 operates tomodulate the signal developed in oscillator 28. The circuitry of audiofrequency oscillator 27 and radio frequency oscillator 23 and theircoupling is shown in detail in Fig. 3 which will be described below.

Referring again to Fig. 2 it is seen that amplifier 29 receives themodulated radio frequency signal from oscillator 28 and after amplifyingthis signal applies it to antenna 30 which is the output of theemergency signaling device. The signal transmitted from this antenna isreceived at a receiver (not shown in the figures) where the coded signalis interpreted.

The circuitry of audio frequency oscillator 27 and radio frequencyoscillator 28 and their coupling will be now described with referencebeing had to Fig. 3.

Power from lead 26 is applied to resistor 31 thereby furnishing A. C.power and enabling the audio frequency oscillator and the radiofrequency oscillator to oscillate. The audio frequency oscillatorutilizes triode vacuum tube 32. Condenser 33 and inductance 34 comprisea tank circuit which determines the frequency of oscillation of theaudio oscillator. Condenser 35 couples this tank circuit to the grid oftube 32, and resistance 36 serves as a grid leak resistor. Triode vacuumtube 32 with its associated components generates a sinusoidal voltage atan audio frequency which is determined by the tank circuit composed ofinductance 34 and capacitor 33.

During any period when power is applied at lead 26 coincidental with andas a result of the generation of audio frequency voltage is the changingof the internal plate to cathode capacitance of vacuum tube 32. Thiscontrolled plate to cathode capacitance change is coupled through fixedcapacitance 37 to variable capacitance 38. This is shown in Fig. 4 wherethe plate to cathode capacitance of tube 32 is indicated by anequivalent condenser designated 39. I Triode vacuum tube 40 togetherwith its associated circuitry and crystal 41 comprise a crystalcontrolled radio frequency oscillator. Inductance 42 and condenser 38compose its plate tank circuit. Variations of capacitance 39 change, theresonant frequency of the plate tank circuit comprised of inductance 32and capacitor 33.

The first oscillator serves as a simple audio tone generator whichchanges the internal plate to cathode capacitance of tube 32, regularlyand sinusoidally with the amplitude of audio signal. The firstoscillator acts as a capacitor in series with the tank circuit of thesecond oscillator and the combination by its tuning determines thefrequency of the radio frequency oscillations (insofar as crystal 41 canbe pulled). As the capacitance of the first oscillator tube changes thetuning of the tank circuit changes and the frequency of the radiofrequency oscillator changes as the crystal is pulled. Therefore theradio frequency oscillators frequency of oscillation i varied above andbelow the mean frequency of the crystal within the allowable frequencyexcursion of the crystal.

Varying the resonant frequency of plate tank circuit 38'42 above andbelow the natural frequency of crystal 41 within the allowable limits ofcrystal 41 results in a variation in the frequency at which the radiofrequency oscillator is oscillating and since this variation isimpressed on the radio frequency wave by the audio frequencyoscillation, an audio frequency modulated radio signal is developed atcoil 43 which is transmitted to amplifier 29 and thence to antenna 30.

Therefore, it is seen that no signal appears at antenna 30 during thoseperiods when the power generator is not operating or, if the powergenerator be operating when coder 20 is preventing transmittal of D. C.power to audio frequency oscillator 27 and radio frequency oscillater28. However, duringany period when D. C. power is applied to both theaudio frequency oscillator and the radio frequency oscillator, afrequency modulated signal appears at antenna 30.

A radio frequency signal therefor can be transmitted merely by anoperator turning crank 13. The power required to operate this system issupplied by hand-operated generator 17 which is voltage regulated andactual use of the system to transmit intelligent coded signals iseffected by code disk on the generator shaft.

Since the unit is complete in itself and compact it may be easily placedat any spot and any one of a number of coded messages may be transmittedsimply by having different coded disks at each generating station andthese coded disks may be easily changed to alter the signal from anygenerator. Also since the frequency is controlled by a crystal, it isprecise and accurate and since the system is of the simple on or olftype, variations will not occur due to usage or non-usage.

Thus, among others, theseveral objects in the invention as specificallyaforenoted are achieved. Obviously, numerous changes in construction orarrangement of the parts might be resorted to without departing from-thespirit of the invention as defined by the claim.

Iclaim: In an emergency signaling device a triode vacuum tube, aninductor connected between the grid and plate I of said vacuum tube, acapacitance connected in parallel with said inductor, a secondcapacitance connected in series between the combination of saidinductorand said first capacitance and the control grid of said vacuumtube, a grid resistance connecting the grid of said tube to the cathodeof said tube, said inductor and said first capacitance being of suchvalues that oscillations at certain audio frequencies can occur in saidvacuum tube; a direct current voltage lead connected to said inductorfor applying direct current voltage thereto, a second triode vacuumtube, a second inductor connected between the plate of said secondvacuum tube and said direct current voltage lead, a third capacitanceconnected between the plate of said second vacuum tube and a cathode ofsaid second vacuum tube, said second inductor and said third capacitancebeing of such values that they can achieve a resonant frequency, a thirdinductor coupled to said second inductor, a quartz crystal in serieswith said third inductor, the values of said third inductor and saidquartz crystal being such as to enable resonance to be achieved at aradio frequency close to the resonant frequency of the combination ofsaid second inductor and said third capacitance; a fourth capacitanceconnecting the plate of said first vacuum tube and the plate of saidsecond vacuum tube, the value of said capacitance being such as to offerminimum reactance to the audio frequency oscillations generated by saidfirst vacuum tube and which permit the resulting changing plate tocathode capacitance of-said first vacuum tube to be coupled in parallelwith said second inductor and said third capacitance and the resultantchanging grid to cathode capacitance of said second vacuum triode to becoupled in parallel with said third inductorand said quartzcrystal inphase with the changing capacitance of said second inductor and saidthird capacitance combination; and means for energizing said directcurrent voltage lead.

References Cited in the file of this patent UNITED STATES PATENTS1,930,046 Hammond Oct. 10, 1933 2,394,393 Mayer Feb. 5, 1946 2,531,103Beckwith Nov.'2l, 1950 2,558,343 Cosby June 26, 1951 2,601,436.Hugenholtz June 24, 1952 2,647,991 Tatel et al. Aug. 4, 1953 2,775,703Bourgonjon Dec. 25, 1956 F R GN PATE TS 567,334 Great Britain Feb. 8,1945

